According to legend, it was of Argive origin. Strabo's assertion that the population, the Falisci, were of a different race from the Etruscans is supported by the language of the earliest inscriptions which have been found here. 
At the beginning of the historical period at the start of the 5th century BC, and no doubt earlier, the dominant element in the town was Etruscan. Through the wars of the following centuries the town was counted as a member, and sometimes a leading member, of the Etruscan league.
Wars between Rome and the Falisci appear to have been frequent. To one of the first belongs the story of the schoolmaster who wished to betray his boys to Camillus; the latter refused his offer, and the inhabitants thereupon surrendered the city. At the end of the First Punic War, the Falisci rose in rebellion, but were soon conquered (241 BC) and lost half their territory.
According to Zonaras (viii. 18), the ancient city, built upon a precipitous hill, was destroyed and another built on a more accessible site on the plain. The description of the two sites agrees well with the usual theory that the original city occupied the site of the present Civita Castellana, and that the ruins of Falerii (as the place is now called) are those of the Roman town which was thus transferred five kilometers to the north-west, in the comune of Fabrica di Roma.
After this time Falerii hardly appears in history. It became a colony (Junonia Faliscorum) perhaps under Augustus, though according to the inscriptions apparently not until the time of Gallienus (who may have been born there). There were bishops of Falerii up till 1033, when the desertion of the place in favour of the present site began. The last mention of it dates from 1064.
The site of the original Falerii is a plateau, about 1100 m by 400, not higher than the surrounding country (140 m) but separated from it by gorges over 60 m in depth, and only connected with it on the western side, which was strongly fortified with a mound and ditch. The rest of the city was defended by walls constructed of rectangular blocks of tuff, of which some remains still exist. Remains of a temple were found at Lo Scasato, at the highest point of the ancient town, in 1888, and others have been excavated in the outskirts.
The attribution of one of these to Juno Quiritis is uncertain. These buildings were of wood, with fine decorations of coloured terracotta. Numerous tombs hewn in the rock are visible on all sides of the town, and important discoveries have been made in them; many objects, both from the temples and from the tombs, are in the Museo di Villa Giulia at Rome. Similar finds have also been made at Calcata, ten kilometers to the south, and Corchiano, around ten kilometers north-west.
The site of the Roman Falerii is now entirely abandoned. It lay upon a road which may have been the Via Annia, a by-road of the Via Cassia; this road approached it from the south passing through Nepet, while its prolongation to the north certainly bore the name Via Amerina. The circuit of the city is about 2000 m, its shape roughly triangular, and the walls are a remarkably fine and well-preserved specimen of Roman military architecture.
The Roman town lay five kilometers farther north-west on the Via Annia. The Via Flaminia, which did not traverse the Etruscan city, had two post-stations near it, Aquaviva, some 4 km southeast, and Aequum Faliscum, around six kilometers north-north-east; the latter is very possibly identical with the Etruscan site which George Dennis identified with Fescennia. There were about 80 towers, some 50 of which are still preserved. Two of the gates also, of which there were eight, are noteworthy. Of the buildings within the walls hardly anything is preserved above ground, though the forum and theatre (as also the amphitheatre, the arena of which measured 55 by 33 meters outside the walls) were all excavated in the 19th century. Almost the only edifice now standing is the late 12th century abbey church of S. Maria, built by monks from Savoy. Excavations undertaken in the late 19th and into the early 20th century indicated that the plan of the whole city could easily be recovered, though the buildings have suffered considerable devastation.
- This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). Encyclopædia Britannica (11th ed.). Cambridge University Press.
- Gabriël C. L. M. Bakkum (1 December 2008). The Latin Dialect of the Ager Faliscus: 150 Years of Scholarship. Amsterdam University Press. pp. 43–. ISBN 978-90-5629-562-2.
- Livy iv. 23, V. 17, vii. 17.
- See also Roman Catholic Diocese of Civita Castellana and List of the Roman Catholic dioceses in Italy.
- Maristella Pandolfini Angeletti (2006). Archeologia in Etruria meridionale: atti delle giornate di studio in ricordo di Mario Moretti : Civita Castellana, 14-15 novembre 2003. L'ERMA di BRETSCHNEIDER. pp. 91–. ISBN 978-88-8265-365-1.
- George Dennis, Cities and Cemeteries of Etruria (London, 1883), i. 121.
- Notizie degli scavi, 1903, 14.